1. Field of the Invention
The invention relates to an electrical connector, and more particularly to an electrical connector having a metal housing.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a dual-layer USB (Universal Serial Bus) electrical connector into which a convention USB plug is inserted includes a plastic base 10, a metal housing 20 and a front fitting part 30. The plastic base 10 has a baffle 11 and two connection slots 12 at a front end thereof. A plurality of terminals 13 is disposed in the plastic base 10. The metal housing 20 covers the plastic base 10 and enables the connection slots 12 of the plastic base and a pin portion of each terminal 13 to be exposed to the outside. The metal housing 20 has top and bottom surfaces each formed with two elastic engaging pieces 21 by way of pressing. The elastic engaging piece 21 is formed with a projecting engaging portion 22 at a portion near a distal end thereof, two elastic grounding pieces 23 at two side plates thereof by way of pressing, fastening hooks 24 at two sides of the bottom end thereof, and engagement holes 25 at two sides of the front end thereof. The front fitting part 30 has a -shaped cross-sectional area and is formed with two elastic engaging pieces 31 at two surfaces thereof. The elastic engaging piece 31 is formed with a projecting engaging portion 32 at a portion near a distal end thereof and hooks 33 at two sides thereof. The baffle 11 of the plastic base 10 is fit into the front fitting part 30, and the hooks 33 hook the engagement holes 25 of the metal housing 20.
According to the above-mentioned structure, when the USB plug 35 is inserted into the connection slot 12, the engaging portions 22 of the two elastic engaging piece 21 of the metal housing 20 and the two engaging portions 32 of the two elastic engaging pieces 31 of the front fitting part 30 engage with the engagement holes 36 formed at the two surfaces of the USB plug 35.
The prior art structure has the following drawbacks.
1. Each of the top and bottom surfaces of the metal housing 20 is pressed to form two elastic engaging pieces 21 for engaging with the engagement holes 36 of the USB plug 35, and the lower edges of the metal housing 20 are integrally extended to form the fastening hooks 24. So, the plastic engaging pieces 21 and the fastening hooks 24 must have the proper intensity in order to achieve the stable engaging and hooking effects. In this way, the metal housing 20 cannot be formed by a thinner plate, or the elastic engaging piece 21 and the fastening hook 24 may have insufficient intensity and elasticity, and the effect of saving the material cannot be achieved.
2. Because the fastening hooks 24 are integrally formed at the lower edges at two sides of the metal housing 20 by way of pressing, the two side plates have to be long enough such that the fastening hooks 24 can be formed, and the material is thus wasted.
3. Because the fastening hooks 24 are integrally formed at the lower edges at two sides of the metal housing 20, tin has to be plated on the fastening hooks 24 such that the fastening hooks 24 may be electrically connected to the circuit board. Thus, the plating cost has to be added.
4. As shown in FIG. 3, when the USB plug 35 is pulled out and thus pushes the elastic engaging pieces 21 and 31, the elastic engaging pieces 21 and 31 elastically move according to the elasticity thereof, and the baffle 11 is not pressed. The engaging intensity completely comes from the intensity thereof, so each of the elastic engaging pieces 21 and 31 must have the sufficient thickness to provide the sufficient engaging force.